The design of stairlifts necessarily involves a number of compromises. One compromise arises from the need to minimize the intrusion of the stairlift into the stairway. This rises in significance when the stairway is narrow and there is a risk that a user, particularly the user's knees or feet, will come into contact with the stairway during movement of the stairlift up and down the stairway.
A further compromise arises from the need to accommodate users whose knee and/or ankle flexure is impaired. In some cases, assuming a fully seated position may cause a user pain or other discomfort.
Conventionally, a stairlift proceeds up and down a rail mounted on a stairway with the user seated facing in a direction perpendicular to the direction of motion, and the user's knee joints substantially defining right angles. Not only does this configuration maximize the intrusion of the user into the stairway but it also requires considerable knee flexure which can be painful.
Published International Patent Application No. WO2005/087644 seeks to address the intrusion problem by providing a mechanism that pivots the stairlift chair about a vertical axis during movement of the stairlift along the rail, the pivot angle being dependent on the position of the stairlift along the rail. European Patent Application No. 2 119 660 describes an arrangement in which the chair can not only be pivoted to face in a downward direction, but can also be lowered and slanted backwards to provide increased clearance between a passenger and a ceiling overlying the stairway.
Whilst the two patent applications mentioned above address the issue of narrow stairways, each presents a problem in that it is generally considered undesirable for a stairlift to be facing in a downwards or downhill direction whilst in motion. This is because, in the event of a malfunction in the stairlift, the stairlift could come to a halt at some point in its journey. In this event a passenger would be exposed to additional danger if he/she attempted to dismount from the stairlift, because the distance from the chair to the adjacent (downhill) part of the stairway is that much greater than when the stairlift is in the more conventional configuration. A further problem with both proposals is that they do nothing to limit the flexure of a user's knees.
The issue of knee flexure is addressed by stairlifts in which the user stands, supporting his/her own weight, during the journey. This leads to safety concerns, it being generally accepted that users should be positively supported during a stairlift journey. A variation of the standing stairlift, and one which offers a degree of support, is the perch stairlift where the user's bottom is partly supported. This form of stairlift requires the user to push back on the perch and, in the event the user looses his/her footing, gravity will cause the user to be displaced from the perch and, potentially, ejected from the stairlift.
It is an object of the present invention to provide a method of supporting a stairlift user, and/or a stairlift, that will go at least some way to addressing the aforementioned drawbacks; or which will at least provide a novel and useful choice.